EightBall

this is my second trans am. my first was a 2000 trans am and the current is a 2002 ws6. in both cars, Ive heard a clicking noise when I first started the car, particularly if the engine was already warm. is this the piston slap Ive been hearing about? I brought both cars to my dealer several times, none of the times did they "hear the same thing" of course whats the damage that could be caused by this, if any? is there any proof this even exists so that I can go to my dealer and have them fix it? thanks